The HETS-IP - Expandable Internal Patch
The HETS Internal Patch (IP) for casing, liner or tubing is a metal sleeve (e.g. 6mm thick 316 Stainless Steel), which is conveyed downhole, on coiled tubing, wireline or drill pipe, via attachment to the HETS expansion tool. The IP is used to repair corroded or damaged tubulars or to block off screens or isolate perforated zones. When positioned on depth; the patch is plastically expanded by direct hydraulic pressure generated between the upper and lower seals of the HETS tool. At final set pressure, the patch will conform to the inside surface of the casing/liner/tubing wall. The resultant high interfacial pressure creates an interference fit acting between the casing / liner and the patch.
The interference fit achieved along the internal patch body provides a large metal-to-metal contact area for pressure sealing, an internal mechanical support to corroded or weakened casing/liner and a high axial resistance of the patch moving along the wellbore. The patch material and thickness are selected to meet specific well requirements.
READ also provides HETS-Slim Patch solutions for wells with 4.5’’ up to 5.5’’ tubulars, which are based around a single size of electro-hydraulic power pack and two sizes of HETS seal assembly. The system is well tractor compatible for deployment in high angle or horizontal wells on wireline or stiff-wire coiled tubing. The patch diameter has been designed to cover a targeted maximum of 20% expansion range (on diameter). The HETS tool is modular in design to allow for different lengths of patch.
Key benefits
- Permanently repairs leaking casing or tubing even in gas wells
- Minimal restriction in the well (when compared to conventional straddle)
- Provides high resistance to axial load
- Shut off water production but maintain well access
- Strengthens damaged or corroded liner
- Repair and seal liner even when it is deformed
